Pharmacology Cito

Pharmacology Cito 5 Read: it is important! Dear future physicians and pharmaceutists! The scientific and pedagogical staff of the Pharmacology department of the National University of Pharmacy (Kharkiv) presents a new textbook "Pharmacology – Cito!" to you. We want to change the myth that it is impossible to learn pharmacology quickly and qualitatively. The textbook "Pharmacology – Cito!" is published for those, who have decided to connect his or her profession with medicines, but think that a great amount of the information in pharmacology is hard to learn. Taking this fact into account we have decided to help those, who wish to master pharmacology in logical, fast - "Cito!"- version. Not be afraid of pharmacology! The 40-year experience of teaching pharmacology testifies that for the last 10-15 years a tendency of reducing the amount of classroom hours in pharmacology because of increasing the amount of the individual work is being observed. However, because of the lack of time and the constant increasing volume of information in pharmacology, everyone has not enough time to master it soundly and qualitatively. This textbook trains future pharmaceutists and physicians in the pharmacological logic, i.e. knowing the mechanisms of drug action one can understand their pharmacodynamics, naturally, on the basis of pharmacodynamics one can find logically the indications to their application and from their side effects the contraindications can be seen. The information about the peculiarities of medicines has been generalized and given as a pharmacological ―face‖ in tables. The volume of this textbook in pharmacology is sufficient for acquiring the confidence in the opportunity of the further improving of knowledge in this discipline, which is important for a physician and a pharmaceutist. Here we have concentrated such amount of information that is necessary enough for getting a pharmacological "portrait" of new and traditional medicines; we have provided physicians, pharmaceutists and students with the algorithm of the pharmacological logic, thinking and intuition. Today the assortment of medicines, which a physician and a pharmaceutist are ―armed‖ with, is more than 400 thousand trademarks. The textbook gives the information on those blockbusters, brands and generics of the world pharmacy, without knowing them either a physician or a pharmaceutist cannot ―step over the threshold‖ of a ward and a chemist’s shop; every physician and pharmaceutist should know them. Frequently the insufficient survivability of knowledge in the basic subjects (pathology, physiology, biochemistry) has obliged us to help those, who had lost this knowledge. That’s why in the section "Glossary" we have reminded you the terms and concepts, which you had known, but forgot. The unique feature of this textbook is the presentation of the information, which corresponds to the credit-module organization of the academic process according to the European educational standards. This textbook is the first step for those, who want to succeed in pharmacotherapy, to master the pharmacological logic. Despite of the conciseness description of a "pharmacological face" of each pharmacological group all the elements of the drug characteristics in the textbook (INN and trade names, the mechanism of action, pharmacodynamics, indications, side effects and contraindications) are presented at the advanced up-to-date level. The authors hope that "Pharmacology – Cito!" (the pharmacological logic) will be the start for further improving your pharmacological knowledge. This edition is intended for students, physicians and pharmaceutists, who want to catch everything in this life! With sincere hope for mutual understanding, professor S. Drogovoz Special thanks to Pozdnyakova A.Yu., Sadovnikova M.V., Labuzova Yu.V. 6 GENERAL PHARMACOLOGY (“PHARMACOLOGICAL ALPHABET”) PHARMACOLOGY AND ITS BASIC TERMS Pharmacology in its literal translation means ―the science about medicines‖ (Pharmakon in Greek is ―medicine, poison‖; logos in Latin means ―science‖). Nowadays pharmacology is a complex science studying the action of medicines on healthy and diseased organisms, the science about the purposeful search of new medicines and their rational use. A future physician and a pharmaceutist must understand clearly the actual meaning of common terms (approved by the WHO), which characterize drugs and changes in the organism occurred after their introduction. A medicine (drug, medication, remedy, medicinal agent) is a pharmacological agent in a definite medicinal form approved for application with the purpose of treatment, prophylaxis and diagnostics of diseases. A medicinal substance is an individual pharmacological substance approved for application. A pharmacological substance is an individual substance with the pharmacological activity under research. A pharmacological agent (remedy) is a pharmacological substance or their combination in a definite medicinal form under research. Other names of medicines are pharmaceutical agent, physiologically, biochemically and pharmacologically active substance. These names are lame or unpractical synonyms for the word ―medicine‖. A medicinal form is the form of a medicine, which is convenient for use, appropriate for the aims of therapy and provides the required effect. Medicines introduced into the organism interact with the cell receptors, as a result functions of cells intensify (stimulate) or suppress (inhibit). The intensification or suppression of biophysical, biochemical and physiological processes in a cell under the action of medicines is called a pharmacological reaction. A pharmacological effect is the result of the successive changes in the functions of the organism’s organs and systems under the action of medicines. The complex of changes (pharmacological effects), which takes place in the organism under the influence of medicines, is called pharmacodynamics or pharmacological properties of a medicine. The method, by which a medicine’s pharmacological effect is achieved, is called the mechanism of its action. THE MECHANISM OF DRUGS’ ACTION To reveal its pharmacological effect that is realized via the mechanism of action, a medicine must contact with molecules of the organism’s cells. A contact of a medicine with a biological substrate – ligand (ligo means ―to connect‖) can occur with the help of chemical, physical, physicochemical interaction. Receptors, enzymes, ion channels, transport systems and others are the primary ―targets‖ for medicines. Receptors are specific cell structures, which provide the interaction between a medicine and the organism. They interact only with medicines that have a certain chemical structure, i.e. they possess the property of selectivity. 7 The typical mechanisms of drug and receptor interaction: 1. A medicine that has structural similarity to a metabolite (for example, mediator) interacting with the receptor promotes its excitation (imitating the mediator’s action). Such medicine is called agonist (in Greek agonistes is ―a rival‖, agon is ―a struggle‖) or mimetic (in English ―to mimic‖). Durability of a medicine binding to certain receptors is stipulated by their structure and it is termed as “affinity” (in Latin affinis is ―relative‖). 2. A medicine is similar to a metabolite; it binds to a receptor, but does not give a chance to a true metabolite to bind to a receptor causing effects opposite to the metabolite. Such medicines are called antagonists or blockers (antagonista is ―rivalry‖). 3. Acting on the receptors medicines can combine the properties of agonists and antagonists. In this case they are called agonists-antagonists. 4. When interacting with the receptor’s allosteric centre medicines promotes the conformational changes in the structure of the receptor modifying its sensitivity to the organism’s metabolites. They are medicines - modulators. Many medicines modify the functioning of the ion channels. One of the ―targets‖ for medicines are potential-depending ion channels that conduct Na+, K+, Ca2+ selectively through the cell membrane. Medicines can block potential-depending ion channels (break the penetration of ions by channels through the cell membrane) or activate these channels (assist their opening and passing of ion flows). The variants of the drug action mechanisms listed above do not exhaust all possibilities of their interaction with the body cells. Nowadays the mechanism of action has not been found for all medicines. TYPES OF THE DRUG ACTION To analyze complex and various phenomena of pharmacodynamics there are several types of the drug action. Local (preresorptive) action is all changes occurring in the site of the drug application. The local action is revealed if a medicine is applied on the skin, mucous membranes and is directly introduced into organs. It should be remembered that the local action cannot be considered separately from the reaction of the whole organism. The local action is characterized, for example, by astringent, irritant, cauterant, local anesthetic effect of medicines. To reveal the local action ointments, gels, solutions for external use, powders, pastes, liniments and plasters are often used. The resorptive action (in Latin resorbeo means ―I absorb‖) appears when a medicine absorbs in the blood and can develop effects in the different organs and tissues that it interacts with. There is a direct and indirect resorptive action. The direct action is the effect caused by a direct influence of a medicine on the target organ. The indirect effect appears indirectly in

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